Information processing apparatus, information processing system, and recording medium storing program

ABSTRACT

An information processing apparatus includes: a memory; and a processor coupled to the memory and configured to: perform mirroring of data with a first information processing apparatus and switches from a standby system to an active system with operation shutdown of the first information processing apparatus to operate as a second information processing apparatus, the information processing apparatus; determine whether or not target data is data for which the mirroring is completed before the operation shutdown, the target data being target data of a restoration copy processing performed when the first information processing apparatus is restored to the active system after the information processing apparatus operates as the second information processing apparatus; and copy the target data from the own apparatus to the first information processing apparatus when determining that the target data is data for which the mirroring is completed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of theprior Japanese Patent Application No. 2019-213846, filed on Nov. 7,2019, the entire contents of which are incorporated herein by reference.

FIELD

The embodiment discussed herein is related to an information processingapparatus, an information processing system, and a recording mediumstoring a program.

BACKGROUND

In a cluster system having a data replication configuration, in responseto a data write request from an application, an active informationprocessing apparatus completes a write processing to a slice of astandby information processing apparatus and then makes a writecompletion reply to the application. The cluster system is a system inwhich multiple information processing apparatuses are operated as onesystem by cooperating with each other. The cluster system having thedata replication configuration is a cluster system in which data writtenin a slice of an active information processing apparatus is also writtenin a slice of a standby information processing apparatus. The slice is avolume stored in each of the active information processing apparatus andthe standby information processing apparatus. The slice stored in theactive information processing apparatus and the slice stored in thestandby information processing apparatus form a mirroring pair of thevolume.

Examples of the related art include Japanese Laid-open PatentPublication Nos. 2019-82897 and 2009-266120 and InternationalPublication Pamphlet No. WO 2015/198449.

SUMMARY

According to an aspect of the embodiments, an information processingapparatus includes: a memory; and a processor coupled to the memory andconfigured to: perform mirroring of data with a first informationprocessing apparatus and switches from a standby system to an activesystem with operation shutdown of the first information processingapparatus to operate as a second information processing apparatus, theinformation processing apparatus; determine whether or not target datais data for which the mirroring is completed before the operationshutdown, the target data being target data of a restoration copyprocessing performed when the first information processing apparatus isrestored to the active system after the information processing apparatusoperates as the second information processing apparatus; and copy thetarget data from the own apparatus to the first information processingapparatus when determining that the target data is data for which themirroring is completed.

The object and advantages of the invention will be realized and attainedby means of the elements and combinations particularly pointed out inthe claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a configuration of a cluster systemaccording to an example;

FIG. 2 is a diagram illustrating a functional configuration of a diskcontrol unit;

FIG. 3A is a diagram illustrating an example of a failure informationstorage unit;

FIG. 3B is a diagram illustrating relationships among a class, volumes,and slices;

FIG. 4 is a diagram illustrating a sequence of a restoration copyprocessing;

FIG. 5 is a flowchart illustrating a flow of the restoration copyprocessing;

FIG. 6 is a diagram illustrating a hardware configuration of a computerthat executes a disk control program according to the example;

FIG. 7 is a diagram for explaining slice preceding fallback;

FIG. 8 is a diagram illustrating a state where a server is in a shutdownstate after the slice preceding fallback;

FIG. 9 is a diagram illustrating a state where data is written to aserver; and

FIG. 10 is a diagram illustrating occurrence of data loss.

DESCRIPTION OF EMBODIMENTS

When a cluster partition occurs in the cluster system having the datareplication configuration, an error occurs in the write processing tothe slice of the standby information processing apparatus and processingof the application is interrupted with the data writing not beingcompleted. The cluster partition is a state in which communicationbetween the information processing apparatuses in the cluster system isdisrupted. As a technique of reducing interruption in the processing ofthe application when the cluster partition occurs, there is slicepreceding fallback.

FIG. 7 is a diagram for explaining the slice preceding fallback. In FIG.7, two servers 91 referred to as a server #11 and a server #12 areinformation processing apparatuses that construct a cluster system 9having the data replication configuration. The server #11 is the activeinformation processing apparatus and the server #12 is the standbyinformation processing apparatus.

In each server 91, an application 21 is running. The application 21writes data to slices of a disk device 23 and reads data from the slicesof the disk device 23 via a cluster control unit 92. The cluster controlunit 92 performs processing relating to the cluster system 9 andincludes a disk control unit 90.

The disk control unit 90 controls writing of data to the slices of thedisk device 23 and reading of data from the slices of the disk device23. When the disk control unit 90 of the server #11 writes data to theslices of the own apparatus, the disk control unit 90 writes data alsoto the slices of the server #12. For example, the disk control unit 90performs mirroring.

When the server #11 and the server #12 are unable to communicate witheach other, the disk control unit 90 of the server #11 fails to writedata to the slices of the server #12. The disk control unit 90 of theserver #11 then performs the slice preceding fallback. For example, thedisk control unit 90 of the server #11 writes information identifyingeach of the slices to which data writing has failed, to the disk device23 as failure disk information, and gives a reply of write completion tothe application 21.

Performing the slice preceding fallback when the disk control unit 90 ofthe server #11 fails to write data to the slices of the server #12 asdescribed above enables reduction of the interruption in the processingof the application 21. However, the slice of the disk device 23 in theserver #12 is left outdated.

As a technique that is relevant to remote copying of data, there is atechnique of improving the availability of an information systemincluding multiple storage apparatuses. In this information system,first and second storage devices respectively internally set a pair ofremote copies that copy the data of the first volume of the firststorage device to the second volume of the second storage device. Thefirst and second storage apparatuses associate the remote copy pair witha third volume in a third storage apparatus. When an I/O request to thefirst volume fails, a host computer sends the second storage apparatusan I/O request to the second volume. When the first or second storageapparatus detects a failure in the other one of the first and secondstorage apparatuses or detects a coupling failure between the first andsecond storage apparatuses, the first or second storage apparatus storesa failure information flag indicating detection of the failure, in thethird volume.

As another technique, there is a storage system that enables operationof an Active/Active configuration and that is capable of takingappropriate measures in the case of a failure. This storage systemincludes a first storage apparatus and a second storage apparatus eachhaving one or more volumes, and a third storage apparatus accessible bythe first storage apparatus and the second storage apparatus. Thestorage system operates to copy data written from the host to a volumein the first or second storage apparatus to a volume in the other one ofthe first and second storage apparatuses. The first storage apparatusand the second storage apparatus periodically write health checkinformation to the third storage apparatus. When the first storageapparatus receives a write request from the host but fails to copy thewrite data to the second storage apparatus, the first storage apparatusreads the health check information written in the third storageapparatus. The first storage apparatus confirms that the volume of thesecond storage apparatus is I/O disabled, and then resumes processingrelating to the write request from the host.

When the server #11 shuts down after the execution of the slicepreceding fallback illustrated in FIG. 7, the server #12 becomes theactive system and the slices of the server #11 are detached asillustrated in FIG. 8. The application 21 then runs on the server #12 tocontinue tasks. Since the slices of the server #12 are in an outdatedstate, the application 21 of the server #12 may not be able to correctlyoperate. Accordingly, in this case, the application 21 is assumed toperform, for example, tasks that are more important to continue for acertain period of time than to be interrupted even if the data ispartially outdated and that use data in the latest state after a lapseof a predetermined period of time.

When the tasks are continued and new data is written in the slices ofthe server #12, as illustrated in FIG. 9, the slices of which one of theserver #11 and the server #12 are the latest becomes unclear. Forexample, part of data is the latest in the slices of the server #11 andthe other part of the data is the latest in the slice of the server #12.

When the server #11 is restored in this state, the data in the slices ofthe server 12# is copied to the slices of the server #11 to equalize thedata in the slices of the server #11 and the data in the slices of theserver #12. Part of the latest data in the server #11 is then replacedwith the outdated data in the server #12 and data loss occurs asillustrated in FIG. 10.

Data loss when an active information processing apparatus that hasexecuted slice preceding fallback is restored after shutdown may besuppressed.

Hereinafter, an example of an information processing apparatus, aninformation processing system, an information processing method, and aprogram disclosed in this application is described in detail withreference to the drawings. This example does not limit the disclosedtechnique.

Example

First, a configuration of a cluster system according to the example isdescribed. FIG. 1 is a diagram illustrating the configuration of thecluster system according to the example. As illustrated in FIG. 1, thecluster system 1 according to the example includes servers 2 referred toas a server #1 and a server #2. The server #1 and the server #2 arecoupled to each other by a network 3. The cluster system 1 is a clustersystem having a data replication configuration. The cluster system 1 maybe constructed by using three or more servers 2.

An application 21 runs on each of the servers 2. The application 21writes data to slices of a disk device 23 and reads data from the slicesof the disk device 23 via a cluster control unit 22. The cluster controlunit 22 performs processing relating to the cluster system 1 andincludes a disk control unit 30.

The disk control unit 30 controls writing of data to the slices of thedisk device 23 and reading of data from the slices of the disk device23. When the disk control unit 30 of the server #1 writes data to theslices of the own apparatus, the disk control unit 30 writes data alsoto the slices of the server #2. For example, the disk control unit 30performs mirroring.

Next, a functional configuration of the disk control unit 30 isdescribed. FIG. 2 is a diagram illustrating the functional configurationof the disk control unit 30. As illustrated in FIG. 2, the disk controlunit 30 includes a driver 31, an initiator 32, a daemon 33, a failureinformation storage unit 34 a, and a configuration information storageunit 34 b.

The driver 31 controls reading of data from the disk device 23 andwriting of data to the disk device 23. The driver 31 receives a datawrite request from the application 21 and controls writing of data to alocal disk and a remote disk. The initiator 32 writes data to the remotedisk based on an instruction from the driver 31. The driver 31 includesan error notification unit 31 a, a completion notification unit 31 b,and a copy unit 31 c.

When the error notification unit 31 a is notified of occurrence of anI/O error in the data writing from the initiator 32 to the remote disk,the error notification unit 31 a suspends the write processing andnotifies the daemon 33 of the I/O error.

When the daemon 33 that has been notified of the occurrence of the I/Oerror notifies the completion notification unit 31 b of completion ofwriting of failure disk information, the completion notification unit 31b restarts the write processing and notifies the application 21 of thecompletion of the writing.

The copy unit 31 c performs processing of achieving consistency betweenthe local disk and the remote disk by using the failure disk informationat start-up of the server 2 when the other server 2 is normallyoperating.

When one server 2 is restored from a shutdown state to an active systemand the other server 2 returns from the active system to a standbysystem, the copy unit 31 c performs a restoration copy processing ofachieving consistency between the slices of the other server 2 and theslices of the own apparatus in cooperation with the copy unit 31 c ofthe other server 2. In the restoration copy processing, the server 2that returns from the active system to the standby system operates as acopy source server 2, and the server 2 that is restored from theshutdown state to the active system operates as a copy destinationserver 2.

The copy unit 31 c of the server 2 that returns from the active systemto the standby system instructs the other server 2 to write data in theslices stored in the disk device 23 of the own apparatus, as therestoration copy processing. However, since data in the slice whoseidentification information is included in the failure disk informationof the other server 2 is written only in the active server 2 before theshutdown, the copy unit 31 c of the server 2 that returns from theactive system to the standby system outputs warning for this slicewithout setting the slice as a copy target.

The copy unit 31 c of the server 2 that returns from the active systemto the standby system makes an inquiry to the other server 2 anddetermines whether or not the failure disk information of the otherserver 2 includes the information identifying each slice. The copy unit31 c of the server 2 that returns from the active system to the standbysystem also adds, for example, information identifying a volume and amessage prompting a user to confirm which of the slices of therespective two servers 2 is the latest, to the warning.

The copy unit 31 c of the server 2 that is restored from the shutdownstate to the active system checks whether or not the informationidentifying the slice is included in the failure disk information inresponse to the inquiry from the copy unit 31 c of the other server 2,and gives a reply indicating whether or not the information identifyingthe slice is recorded. When the copy unit 31 c of the server 2 that isrestored from the shutdown state to the active system receives the dataof the slice from the copy unit 31 c of the other server 2, the copyunit 31 c of the restored server 2 writes the data to the correspondingslice.

The copy unit 31 c includes a determination unit 41, an execution unit42, and a reply unit 43. When the apparatus including the determinationunit 41 is the server 2 that returns from the active system to thestandby system in the restoration copy processing, the determinationunit 41 makes an inquiry to the other server 2 and determines whether ornot the failure disk information of the other server 2 includes theinformation identifying each slice.

When the determination unit 41 determines that the failure diskinformation of the other server 2 includes the information identifyingthe slice, the execution unit 42 outputs warning. Meanwhile, when thedetermination unit 41 determines that the failure disk information ofthe other server 2 does not include the information identifying theslice, the execution unit 42 sends the data of the slice to the otherserver 2.

When the apparatus including the reply unit 43 is the server 2 thatreturns from the shutdown state to the active system and the reply unit43 receives the inquiry from the other server 2, the reply unit 43refers to the failure information storage unit 34 a and determineswhether or not the failure disk information includes the informationidentifying the slice. The reply unit 43 then sends the determinationresult on whether or not the failure disk information includes theinformation identifying the slice to the other server 2.

The determination unit 41 may receive the failure disk informationinstead of the determination result from the other server 2. Thedetermination unit 41 may acquire the determination result or thefailure disk information for all slices from the other server 2 at once.The reply unit 43 may send the failure disk information instead of thedetermination result in response to the inquiry from the other server 2.The reply unit 43 may send the determination result or the failure diskinformation for all slices at once. The failure information storage unit34 a may also store slice update processing information on slices forwhich mirroring is completed or not completed, as the failure diskinformation.

When receiving an event, the daemon 33 performs processing correspondingto the event. The event includes the I/O error as well as a volumestart-up request, a copy completion notification, and the like.

The failure information storage unit 34 a stores the failure diskinformation. Information in the failure information storage unit 34 amay be accessed from the other server 2. FIG. 3A is a diagramillustrating an example of the failure information storage unit 34 a. Asillustrated in FIG. 3A, the failure information storage unit 34 a storesa class ID, a volume ID, and a Small Computer System Interface (SCSI) IDfor each slice in which the I/O error has occurred, as the failure diskinformation.

The class ID is an identifier identifying a class, the volume ID is anidentifier identifying a volume, and the SCSI ID is an identifieridentifying one of disk devices in a mirroring pair. FIG. 3B is adiagram illustrating relationships among a class, volumes, and slices.As illustrated in FIG. 3B, the disk devices 23 in the mirroring pair aremanaged as a class, and the class includes multiple volumes. Each volumeis formed of slices forming a mirroring pair. Each slice is thusspecified by using the class ID, the volume ID, and the SCSI ID.

The configuration information storage unit 34 b stores configurationinformation. For example, the configuration information storage unit 34b stores information on the configuration of the cluster system 1. Theconfiguration information storage unit 34 b stores a state of eachslice.

The daemon 33 includes a failure information writing unit 35, adetachment unit 36, a start-up control unit 37, and a failureinformation deletion unit 38. When writing of data to the remote diskfails, the failure information writing unit 35 writes the failure diskinformation to the failure information storage unit 34 a. The failureinformation writing unit 35 then notifies the driver 31 that the failuredisk information has been written to the failure information storageunit 34 a. When writing of data to the remote disk fails, the failureinformation writing unit 35 may write information indicating thatmirroring is not completed to the failure information storage unit 34 a.

When writing of data to the remote disk fails, the detachment unit 36detaches a remote slice. For example, the detachment unit 36 acquires acluster lock and changes the configuration information. The detachmentunit 36 detaches the remote slice also when the other server 2 shutsdown and the own apparatus switches from the standby system to theactive system.

The start-up control unit 37 acquires the failure disk informationrecorded in the own server 2 and the failure disk information recordedin the remote server 2 at the start-up of the volume, and updates theconfiguration information based on the acquired failure diskinformation.

When consistency is achieved between the slices in the mirroring pair bythe copy processing, the failure information deletion unit 38 deletesinformation on the slices having achieved consistency from the failuredisk information and changes the states of the slices in theconfiguration information to normal.

Next, a flow of the restoration copy processing is described by usingFIGS. 4 and 5. In FIGS. 4 and 5, a server #1 is the server 2 thatreturns from the shutdown state to the active system in restoration, anda server #2 is the server 2 that returns from the active system to thestandby system. A disk control unit #1 is the disk control unit 30 ofthe server #1, a disk control unit #2 is the disk control unit 30 of theserver #2, a disk device #1 is the disk device 23 of the server #1, anda disk device #2 is the disk device 23 of the server #2. The diskcontrol unit #2 repeats processing illustrated in FIGS. 4 and 5 for allslices stored in the disk device #2.

FIG. 4 is a diagram illustrating a sequence of the restoration copyprocessing. As illustrated in FIG. 4, the disk control unit #2 makes aninquiry to the disk control unit #1 to check whether or not data copy ofa target slice is allowed (t1). When the disk control unit #1 receivesthe inquiry from the disk control unit #2 together with informationidentifying the target slice, the disk control unit #1 checks thefailure information storage unit 34 a (t2), and determines whether ornot the information identifying the target slice is recorded in thefailure information storage unit 34 a. The disk control unit #1 thengives a reply of “recorded” (copy not allowed) or “not recorded” (copyallowed) to the disk control unit #2 as a determination result (t3).

The disk control unit #2 determines whether the reply is recorded (copynot allowed) or not recorded (copy allowed) (t4), and if not recorded,reads the data of the target slice from the disk device #2 (t5) andreceives it from the disk device #2 (t6). The disk control unit #2 thensends the data to the disk control unit #1 and instructs the diskcontrol unit #1 to write the data (t7). The disk control unit #1 havingreceived the data writes the received data to the target slice (t8), andreceives a reply from the disk device #1 (t9). The disk control unit #1then gives a reply of write completion to the disk control unit #2(t10).

The disk control unit #2 then instructs the disk control unit #1 toperform replication incorporation of the target slice (t11). The diskcontrol unit #1 incorporates the target slice into replication (t12),and gives a reply of completion of incorporation to the disk controlunit #2 (t13). The disk control unit #2 then proceeds to the processingof the next slice.

When the reply from the disk control unit #1 is determined to berecorded in t4, the disk control unit #2 outputs warning (t14) andproceeds to the processing of the next slice without sending the data tothe disk control unit #1.

When the restoration copy processing is completed for all slices, theserver #2 switches to the state of standby system. When the restorationcopy processing is completed for all slices, the server #1 switches tothe state of active system.

FIG. 5 is a flowchart illustrating a flow of the restoration copyprocessing. As illustrated in FIG. 5, the disk control unit #2 makes aninquiry to the server #1 to determine whether or not the informationidentifying the target slice is recorded in the server #1. (step S1).When the information identifying the target slice is not recorded, thedisk control unit #2 sends the data of the target slice to the server #1and instructs the server #1 to copy the data (step S2). The disk controlunit #2 then instructs the server #1 to perform replicationincorporation of the target slice (step S3), and proceeds to theprocessing of the next slice.

When the information identifying the target slice is recorded in theserver #1, the disk control unit #2 outputs warning (step S4), andproceeds to the processing of the next slice.

As described above, in the example, when the active server #1 performsslice preceding fallback and then shuts down and the standby server #2switches to the active system, in the restoration of the server #1, thedisk control units 30 of the server #2 and the server #1 perform therestoration copy processing in cooperation. In the restoration copyprocessing, the determination unit 41 of the server #2 determineswhether or not the target slice is a slice for which mirroring is notcompleted before the shutdown and for which data update is not reflectedin the server #2. When the determination unit 41 determines that thetarget slice is not a slice for which mirroring is not completed beforethe shutdown, the execution unit 42 of the server #2 copies the data ofthe slice to the server #1. Accordingly, when there is the latest datain the server #1, the disk control unit 30 of the server #2 may avoidreplacement of the latest data with the outdated data of the server #2and suppress data loss.

In the example, since the determination unit 41 of the server #2 makesan inquiry to the server #1 and determines whether or not the targetslice is a slice for which mirroring is not completed before theshutdown, the cluster system 1 does not have to include another devicefor the restoration copy processing.

In the example, the copy unit 31 c of the server #1 gives a replyindicating whether or not the information for identifying the slice isrecorded in the failure disk information, in response to the inquiryfrom the determination unit 41 of the server #2. Accordingly, thedetermination unit 41 of the server #2 may determine whether or not dataupdate for the slice is performed only in the server #1 before theshutdown and is not reflected in the server #2. This makes it possibleto determine whether or not the mirroring is completed. Accordingly,even in a system that does not use a third server such as a managementserver, a new mechanism in which the server #1 manages the data updateinformation (failure disk information) of the server #1 itself allowsthe server #2, being the copy source in the restoration copy processing,to mainly determine whether or not to allow the copying.

Although the disk control unit 30 has been described in the example, adisk control program having similar functions may be obtained byimplementing the configuration of the disk control unit 30 by software.A computer that executes the disk control program is described.

FIG. 6 is a diagram illustrating a hardware configuration of thecomputer that executes the disk control program according to theexample. As illustrated in FIG. 6, a computer 50 includes a main memory51, a central processing unit (CPU) 52, a local area network (LAN)interface 53, and a hard disk drive (HDD) 54. The computer 50 furtherincludes a super input output (IO) 55, a digital visual interface (DVI)56, and an optical disk drive (ODD) 57.

The main memory 51 is a memory that stores a program, results in middleof execution of the program, and the like. The CPU 52 is a centralprocessing unit that reads the program from the main memory 51 andexecutes the program. The CPU 52 includes a chipset including a memorycontroller.

The LAN interface 53 is an interface that is used to couple the computer50 to another computer through the LAN. The HDD 54 is a disk device thatstores a program and data. The super IO 55 is an interface that is usedto couple input devices such as a mouse and a keyboard. The DVI 56 is aninterface that is used to couple a liquid crystal display device, andthe ODD 57 is a device that reads and writes data from and to a digitalversatile disc (DVD).

The LAN interface 53 is coupled to the CPU 52 by Peripheral ComponentInterconnect Express (PCIe) and the HDD 54 and the ODD 57 are coupled tothe CPU 52 by Serial Advanced Technology Attachment (SATA). The super IO55 is coupled to the CPU 52 by low pin count (LPC).

The disk control program executed by the computer 50 is stored in acompact disc recordable (CD-R) which is an example of a recording mediumreadable by the computer 50, is read from the CD-R by the ODD 57, and isinstalled in the computer 50. Alternatively, the disk control program isstored in a database or the like of another computer system coupledthrough the LAN interface 53, is read from the database or the like, andis installed in the computer 50. The disk control program thus installedis stored in the HDD 54, is loaded into the main memory 51, and isexecuted by the CPU 52.

In the example, the case in which the failure disk information is storedin the active server 2 is described. However, an apparatus other thanthe active server 2 may store the failure disk information as long asthe apparatus is accessible mainly by the copy source server 2 thatperforms the restoration copy processing of the data in the slice forthe restored server 2.

With regard to the embodiment including the aforementioned example, thefollowing appendices are disclosed.

All examples and conditional language provided herein are intended forthe pedagogical purposes of aiding the reader in understanding theinvention and the concepts contributed by the inventor to further theart, and are not to be construed as limitations to such specificallyrecited examples and conditions, nor does the organization of suchexamples in the specification relate to a showing of the superiority andinferiority of the invention. Although one or more embodiments of thepresent invention have been described in detail, it should be understoodthat the various changes, substitutions, and alterations could be madehereto without departing from the spirit and scope of the invention.

What is claimed is:
 1. An information processing apparatus comprising: amemory; and a processor coupled to the memory and configured to: performmirroring of data with another information processing apparatus; switchfrom a standby system to an active system, when an operation of theanother information processing apparatus in the active system isstopped, to operate as the information processing apparatus in theactive system; determine whether target data, which is data on which arestoration copy processing is performed when the another informationprocessing apparatus is restored to the active system after theinformation processing apparatus operates in the active system, is datafor which the mirroring is completed before the operation of the anotherinformation processing apparatus is stopped; and copy the target data tothe another information processing apparatus when determining that thetarget data is data for which the mirroring is completed.
 2. Theinformation processing apparatus according to claim 1, wherein theprocessor determines whether or not the target data is data for whichthe mirroring is completed before the operation of the anotherinformation processing apparatus is stopped by making an inquiry to theanother information processing apparatus.
 3. The information processingapparatus according to claim 2, wherein the processor receives a replyincluding data update processing information of the another informationprocessing apparatus from the another information processing apparatusin response to the inquiry and determines whether the target data isdata for which the mirroring is completed and in which data update inthe another information processing apparatus before the operation of theanother information processing apparatus is stopped is reflected in theinformation processing apparatus or data for which the mirroring is notcompleted and in which the data update is not reflected in theinformation processing apparatus, based on the received reply.
 4. Theinformation processing apparatus according to claim 3, wherein the datais a slice, and the target data for which the mirroring is not completedincludes data for which a write completion reply is made from theanother information processing apparatus to an application by slicepreceding fallback.
 5. An information processing apparatus systemcomprising: a first information processing apparatus and a secondinformation processing apparatus that perform mirroring of data, whereinthe first information processing apparatus operates as an active system,the second information processing apparatus switches from a standbysystem to the active system when an operation of the first informationprocessing apparatus in the active system is stopped, and the secondinformation processing apparatus includes a second processor configureto: make an inquiry on whether or not target data, which is data onwhich a restoration copy processing is performed when the anotherinformation processing apparatus is restored to the active system afterthe information processing apparatus operates in the active system, isdata for which the mirroring is completed before the operation of thefirst information processing apparatus is stopped; and copy the targetdata to the first information processing apparatus when the secondinformation processing apparatus receives a reply that the target datais data for which the mirroring is completed in response to the inquiry,the first information processing apparatus includes a first processorconfigured to: determine whether the target data is data for whichmirroring is completed; and give a reply indicating a result of thedetermination when receiving the inquiry.
 6. A non-transitory recordingmedium storing a program causing an information processing apparatus toexecute processing of: performing, by an information processingapparatus, mirroring of data with another information processingapparatus; switching from a standby system to an active system, when anoperation of the another information processing apparatus in the activesystem is stopped, to operate as the information processing apparatus inthe active system; determining whether or not target data, which is dataon which a restoration copy processing is performed when the anotherinformation processing apparatus is restored to the active system afterthe information processing apparatus operates in the active system, isdata for which the mirroring is completed before the operation of theanother information processing apparatus is stopped; and copying thetarget data to the another information processing apparatus whendetermining that the target data is data for which the mirroring iscompleted.
 7. The non-transitory recording medium according to claim 6,wherein the processing of determining includes determining whether ornot the target data is data for which the mirroring is completed beforethe operation of the another information processing apparatus is stoppedby making an inquiry to the another information processing apparatus.